Australia's Anna Rawson shot a seven-under 64 to take the first-round lead over Suzann Pettersen on Thursday at the LPGA's Canadian Women's Open.

Rawson carded a career-low round on the LPGA Tour to finish a shot ahead of Norway's Pettersen for her second 18-hole lead.

World number one Lorena Ochoa and Amanda Blumenherst were another stroke behind at five-under 66, while Japanese star Momoko Ueda led a four-way tie at 67. American Michelle Wie stumbled to an opening round 76.

Up until this point, the 28-year-old Rawson is better-known for her part-time modelling career than her success on the golf course.

"We didn't have any problems today," she said. "I over-shot one green and it was a perfect shot. I was just in the rough."

Rawson rolled in four birdies and two bogeys and posted a 33 on the front nine. It was on the back nine where she really got going, making birdie on five holes and shooting a 31.

Her previous best career low was a 65 in the final round of the State Farm Classic in June.

"I feel great on this golf course," said Rawson. "I really like all the holes. I feel like you can birdie every one, depending where they put the pins. But I think I've just got a good grasp for it in the practice rounds."

Rawson is a distant 110th on the money list.

"I think this year has just been terrible mentally," she said. "Like, I've just had the worst head that you could ever imagine. I don't even want to tell you what's been going through my head; it's that bad.

"I thought about everything that I shouldn't. I really haven't hit the ball that bad. I just haven't been here. I haven't been enjoying it, I haven't been out here."